Longer Days - A summertime move is a good choice because your days are longer and you can have more daylight to get things done!
No School - Summer is a good time to move because kids are between school time and it won't disrupt their studies, plus, if they are able bodied, they can help with the packing and move too!
Yard Sales - Summer is a big time for yard sales which can be beneficial for you if you sell some things instead of pack them up to move. Also, if you have a Moving Sale in your yard, you may attract some buyers as well!
Peak Selling Season - Summer is the peak time when there are the most sellers and buyers and you can get the best price for your home during this time!